Metal-insulator transitions in strongly correlated oxides such as vanadium dioxide (VO2) are of much scientific and technological interest. Due to the presence of multiple oxidation states, the synthesis of high-quality VO2 films having desired phase transition characteristics such as large jumps in phase transition resistance, is a challenge.
Vanadium dioxide (VO2) is a strongly correlated electron compound that exhibits a dramatic metal-insulator transition (MIT) upon temperature decrease. The MIT occurs close to room temperature. VO2 has been heavily researched because of its relevance to the basic science of metal-insulator transitions. In addition, VO2 is of much interest for applications in electronics, including but not limited to the fabrication of switches, electro-optic devices, and infra-red detectors used in applications such as the defense industry.
An active area of research has thus been to develop high-quality VO2 crystals and thin films, for purposes of understanding their fundamental physical properties, as well as to obtain large changes in the electrical resistance across the phase transition boundary so that high-performance devices can be made. Typically, thin films show less impressive electrical properties compared to single crystals, partly due to the difficulty of synthesizing phase pure VO2 arising from the existence of multiple valence states of V. For practical applications, for example electronics and optoelectronics applications, vanadium oxide thin film structures are more convenient than single crystals.
For these reasons, methods and systems for synthesizing very high quality VO2 thin films with strong MIT properties and sharp phase transition characteristics are very desirable.